Miniature board-to-board electrical connector assemblies are known in the art. Conventionally, a first or receptacle connector is mounted on a first printed circuit board, and a plug or second connector is mounted on a second printed circuit board. The plug connector is inserted into the receptacle connector, with the two printed circuit boards in generally parallel relationship.
For example, such board mounted electrical connectors are used in portable telephones, digital video cameras, digital still cameras or the like. In such small electronic devices, multiple circuit boards are disposed within a narrow confined space, and the connectors are used to provide electrical connection between the boards.
Conventionally, retention means are provided to hold the connectors in mated condition. Heretofore, a retention member having a first engaging portion is mounted on one of the connectors, and a second retention member having an engaging portion is mounted on the other connector. One of the engaging portions on one of the retention members comprises a protrusion which engages a flexible or spring engaging portion on the other retention member, thereby preventing inadvertent decoupling of the connectors. Examples of such retention means are shown in Japanese Patent Documents JP 2004-55306 A (which has a United States counterpart in U.S. Pat. No. 7,128,581); JP 2004-55463 A; JP 11-74024 A (which has a United States counterpart in U.S. Pat. No. 6,466,867); and Utility Model Application Laid-Open No. Hei 5-2385.
With conventional retention means, such as in Japanese Patent Document JP 2004-55306 A, the spring engaging portion on one of the one retention members is relatively long and extends in the mating or height direction of the connectors. This makes it difficult to miniaturize the connectors or reduce the connector heights. If the length of the spring engaging portion is reduced to reduce the height of the connector, a limitation is imposed on the elastic force of the spring engaging portion and causes a large force to act on the base of the spring, resulting in possible elastic deformation of the spring engaging portion. The elastic deformation makes it disadvantageously impossible to retain the connectors in mated condition.
In addition, the retention members often are used as ground terminals between a pair of circuit boards. If the spring engaging portion undergoes elastic deformation, the contact forces between the ground terminals is decreased, making the electrical connection unstable and reducing the reliability of the grounding function. The present invention is directed to solving this myriad of problems.